Wednesday, May 14, 2008

I know! For all my avid readers out there (both of you), it has been just a few days since I have posted. I had three tractor trailers deliver merchandise to BlueStem Winery including a truck just chock full of Cellar Craft wine kits and another from my Ohio wholesaler loaded with winemaking equipment, brewing supplies and WinExpert wine kits. I have pretty much put everything on hold for a few days as I try to unpack, check merchandise and re-stock shelves. Oh, yes, the third truck. Actually, Cellar Craft got one of my pallets on the wrong truck and it went to Texas instead of to Iowa. The store in Texas just kept the pallet and a new pallet of Cellar Craft kits arrived a few days later from Ontario to replace the wayward one.

A question was received from one of my customers who lives in San Antonio, Texas. San Antonio is one of my favorite cities, mostly because it was the only duty station I had other than my year at DaNang, South Viet Nam during my four years in the Air Force. If I remember right, downtown was a mass of one way streets which all met in the center of town. One giant traffic jam! The other thing I remember is gun racks in the back window of every pickup truck. Most likely loaded!

Anyway, my question was as to why my customer's wine was not finishing. When making wine, the wine is usually fermented down to a specific gravity of 1.000 or slightly less and then it is transferred from the primary fermenter (usually a plastic bucket) to the secondary fermenter (usually a 6-gallon glass carboy). The wine then finishes in the carboy down to a specific gravity of 0.992 to 0.994. My customer's wine would ferment down to the 1.000 mark and it (the wine) would be transferred to the carboy where it would ferment down to 0.996 to 0.998 and then stop. It would not finish. He wanted to know why.

The first (or most common) reason is temperature. My customer, however, was maintaining a temperature of 75 degrees F. where the wine was being fermented and this is warm enough. The temperature was being maintained, too. Fluctuations in ambient temperature (as little as 5 degrees F.) can put wine yeast into shock and poor performance (a stuck fermentation) can result. We do not believe either of these to be the cause.

The variety of yeast being used can also be a factor. There are numerous types of wine yeast available and each has its own fermentation character. I know that Cellar Craft typically uses Champagne yeast because it is very forgiving and is very neutral. Champagne yeast can also tolerate wider temperature ranges, high alcohol levels (excessive amounts of alcohol present can also cause a yeast to stop fermenting) and produces smaller amounts of unwanted by-products.

Timing is also important. It is important that home winemaking enthusiasts rack (move their wine from primary to secondary) at the right time. Different wines have different points at which the movement is more advantageous but in this case the target was a specific gravity of 1.000 or less. Try to make this move as close as possible to 1.000 (not over but under 1.000). Above 1.000 can result in excessive foaming. Too far below 1.000 can result in a stuck fermentation right at the end of fermentation. This is very much a possibility for my customer!

Besides racking the wine at the most optimum time as described above, another thing that can be done is to not be toocareful when racking the wine. In other words, do not try to totally avoid racking all of the sediment present in your primary fermenter into the secondary fermenter. Let some of this sludge (sediment) siphon over into your carboy. This small amount of sediment will help provide nutrients for the yeast during this final fermentation stage.

About Me

BlueStem Winery is a licensed Iowa winery which also retails winemaking and home brewing equipment, supplies and ingredients. We blog about wine making and home brewing techniques and about other things as the spirit moves us.